1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 30 * $FreeBSD$ 31 */ 32 33 #include "opt_inet6.h" 34 #include "opt_tcpdebug.h" 35 36 #include <sys/param.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/mbuf.h> 40 #include <sys/mutex.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/socketvar.h> 44 #include <sys/sysctl.h> 45 #include <sys/systm.h> 46 47 #include <net/route.h> 48 49 #include <netinet/in.h> 50 #include <netinet/in_pcb.h> 51 #include <netinet/in_systm.h> 52 #ifdef INET6 53 #include <netinet6/in6_pcb.h> 54 #endif 55 #include <netinet/ip_var.h> 56 #include <netinet/tcp.h> 57 #include <netinet/tcp_fsm.h> 58 #include <netinet/tcp_timer.h> 59 #include <netinet/tcp_var.h> 60 #include <netinet/tcpip.h> 61 #ifdef TCPDEBUG 62 #include <netinet/tcp_debug.h> 63 #endif 64 65 int tcp_keepinit; 66 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW, 67 &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", ""); 68 69 int tcp_keepidle; 70 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW, 71 &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", ""); 72 73 int tcp_keepintvl; 74 SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW, 75 &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", ""); 76 77 int tcp_delacktime; 78 SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime, CTLTYPE_INT|CTLFLAG_RW, 79 &tcp_delacktime, 0, sysctl_msec_to_ticks, "I", 80 "Time before a delayed ACK is sent"); 81 82 int tcp_msl; 83 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW, 84 &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime"); 85 86 int tcp_rexmit_min; 87 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW, 88 &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I", 89 "Minimum Retransmission Timeout"); 90 91 int tcp_rexmit_slop; 92 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW, 93 &tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I", 94 "Retransmission Timer Slop"); 95 96 static int always_keepalive = 1; 97 SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW, 98 &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections"); 99 100 int tcp_fast_finwait2_recycle = 0; 101 SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW, 102 &tcp_fast_finwait2_recycle, 0, 103 "Recycle closed FIN_WAIT_2 connections faster"); 104 105 int tcp_finwait2_timeout; 106 SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW, 107 &tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout"); 108 109 110 static int tcp_keepcnt = TCPTV_KEEPCNT; 111 /* max idle probes */ 112 int tcp_maxpersistidle; 113 /* max idle time in persist */ 114 int tcp_maxidle; 115 116 /* 117 * Tcp protocol timeout routine called every 500 ms. 118 * Updates timestamps used for TCP 119 * causes finite state machine actions if timers expire. 120 */ 121 void 122 tcp_slowtimo(void) 123 { 124 125 tcp_maxidle = tcp_keepcnt * tcp_keepintvl; 126 INP_INFO_WLOCK(&tcbinfo); 127 (void) tcp_tw_2msl_scan(0); 128 INP_INFO_WUNLOCK(&tcbinfo); 129 } 130 131 int tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] = 132 { 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 }; 133 134 int tcp_backoff[TCP_MAXRXTSHIFT + 1] = 135 { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 512, 512, 512 }; 136 137 static int tcp_totbackoff = 2559; /* sum of tcp_backoff[] */ 138 139 static int tcp_timer_race; 140 SYSCTL_INT(_net_inet_tcp, OID_AUTO, timer_race, CTLFLAG_RD, &tcp_timer_race, 141 0, "Count of t_inpcb races on tcp_discardcb"); 142 143 /* 144 * TCP timer processing. 145 */ 146 147 void 148 tcp_timer_delack(void *xtp) 149 { 150 struct tcpcb *tp = xtp; 151 struct inpcb *inp; 152 153 INP_INFO_RLOCK(&tcbinfo); 154 inp = tp->t_inpcb; 155 /* 156 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 157 * tear-down mean we need it as a work-around for races between 158 * timers and tcp_discardcb(). 159 * 160 * KASSERT(inp != NULL, ("tcp_timer_delack: inp == NULL")); 161 */ 162 if (inp == NULL) { 163 tcp_timer_race++; 164 INP_INFO_RUNLOCK(&tcbinfo); 165 return; 166 } 167 INP_LOCK(inp); 168 INP_INFO_RUNLOCK(&tcbinfo); 169 if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_delack) 170 || !callout_active(&tp->t_timers->tt_delack)) { 171 INP_UNLOCK(inp); 172 return; 173 } 174 callout_deactivate(&tp->t_timers->tt_delack); 175 176 tp->t_flags |= TF_ACKNOW; 177 tcpstat.tcps_delack++; 178 (void) tcp_output(tp); 179 INP_UNLOCK(inp); 180 } 181 182 void 183 tcp_timer_2msl(void *xtp) 184 { 185 struct tcpcb *tp = xtp; 186 struct inpcb *inp; 187 #ifdef TCPDEBUG 188 int ostate; 189 190 ostate = tp->t_state; 191 #endif 192 /* 193 * XXXRW: Does this actually happen? 194 */ 195 INP_INFO_WLOCK(&tcbinfo); 196 inp = tp->t_inpcb; 197 /* 198 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 199 * tear-down mean we need it as a work-around for races between 200 * timers and tcp_discardcb(). 201 * 202 * KASSERT(inp != NULL, ("tcp_timer_2msl: inp == NULL")); 203 */ 204 if (inp == NULL) { 205 tcp_timer_race++; 206 INP_INFO_WUNLOCK(&tcbinfo); 207 return; 208 } 209 INP_LOCK(inp); 210 tcp_free_sackholes(tp); 211 if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_2msl) || 212 !callout_active(&tp->t_timers->tt_2msl)) { 213 INP_UNLOCK(tp->t_inpcb); 214 INP_INFO_WUNLOCK(&tcbinfo); 215 return; 216 } 217 callout_deactivate(&tp->t_timers->tt_2msl); 218 /* 219 * 2 MSL timeout in shutdown went off. If we're closed but 220 * still waiting for peer to close and connection has been idle 221 * too long, or if 2MSL time is up from TIME_WAIT, delete connection 222 * control block. Otherwise, check again in a bit. 223 * 224 * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, 225 * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. 226 * Ignore fact that there were recent incoming segments. 227 */ 228 if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 && 229 tp->t_inpcb && tp->t_inpcb->inp_socket && 230 (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) { 231 tcpstat.tcps_finwait2_drops++; 232 tp = tcp_close(tp); 233 } else { 234 if (tp->t_state != TCPS_TIME_WAIT && 235 (ticks - tp->t_rcvtime) <= tcp_maxidle) 236 callout_reset(&tp->t_timers->tt_2msl, tcp_keepintvl, 237 tcp_timer_2msl, tp); 238 else 239 tp = tcp_close(tp); 240 } 241 242 #ifdef TCPDEBUG 243 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 244 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 245 PRU_SLOWTIMO); 246 #endif 247 if (tp != NULL) 248 INP_UNLOCK(inp); 249 INP_INFO_WUNLOCK(&tcbinfo); 250 } 251 252 void 253 tcp_timer_keep(void *xtp) 254 { 255 struct tcpcb *tp = xtp; 256 struct tcptemp *t_template; 257 struct inpcb *inp; 258 #ifdef TCPDEBUG 259 int ostate; 260 261 ostate = tp->t_state; 262 #endif 263 INP_INFO_WLOCK(&tcbinfo); 264 inp = tp->t_inpcb; 265 /* 266 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 267 * tear-down mean we need it as a work-around for races between 268 * timers and tcp_discardcb(). 269 * 270 * KASSERT(inp != NULL, ("tcp_timer_keep: inp == NULL")); 271 */ 272 if (inp == NULL) { 273 tcp_timer_race++; 274 INP_INFO_WUNLOCK(&tcbinfo); 275 return; 276 } 277 INP_LOCK(inp); 278 if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_keep) 279 || !callout_active(&tp->t_timers->tt_keep)) { 280 INP_UNLOCK(inp); 281 INP_INFO_WUNLOCK(&tcbinfo); 282 return; 283 } 284 callout_deactivate(&tp->t_timers->tt_keep); 285 /* 286 * Keep-alive timer went off; send something 287 * or drop connection if idle for too long. 288 */ 289 tcpstat.tcps_keeptimeo++; 290 if (tp->t_state < TCPS_ESTABLISHED) 291 goto dropit; 292 if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) && 293 tp->t_state <= TCPS_CLOSING) { 294 if ((ticks - tp->t_rcvtime) >= tcp_keepidle + tcp_maxidle) 295 goto dropit; 296 /* 297 * Send a packet designed to force a response 298 * if the peer is up and reachable: 299 * either an ACK if the connection is still alive, 300 * or an RST if the peer has closed the connection 301 * due to timeout or reboot. 302 * Using sequence number tp->snd_una-1 303 * causes the transmitted zero-length segment 304 * to lie outside the receive window; 305 * by the protocol spec, this requires the 306 * correspondent TCP to respond. 307 */ 308 tcpstat.tcps_keepprobe++; 309 t_template = tcpip_maketemplate(inp); 310 if (t_template) { 311 tcp_respond(tp, t_template->tt_ipgen, 312 &t_template->tt_t, (struct mbuf *)NULL, 313 tp->rcv_nxt, tp->snd_una - 1, 0); 314 (void) m_free(dtom(t_template)); 315 } 316 callout_reset(&tp->t_timers->tt_keep, tcp_keepintvl, tcp_timer_keep, tp); 317 } else 318 callout_reset(&tp->t_timers->tt_keep, tcp_keepidle, tcp_timer_keep, tp); 319 320 #ifdef TCPDEBUG 321 if (inp->inp_socket->so_options & SO_DEBUG) 322 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 323 PRU_SLOWTIMO); 324 #endif 325 INP_UNLOCK(inp); 326 INP_INFO_WUNLOCK(&tcbinfo); 327 return; 328 329 dropit: 330 tcpstat.tcps_keepdrops++; 331 tp = tcp_drop(tp, ETIMEDOUT); 332 333 #ifdef TCPDEBUG 334 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 335 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 336 PRU_SLOWTIMO); 337 #endif 338 if (tp != NULL) 339 INP_UNLOCK(tp->t_inpcb); 340 INP_INFO_WUNLOCK(&tcbinfo); 341 } 342 343 void 344 tcp_timer_persist(void *xtp) 345 { 346 struct tcpcb *tp = xtp; 347 struct inpcb *inp; 348 #ifdef TCPDEBUG 349 int ostate; 350 351 ostate = tp->t_state; 352 #endif 353 INP_INFO_WLOCK(&tcbinfo); 354 inp = tp->t_inpcb; 355 /* 356 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 357 * tear-down mean we need it as a work-around for races between 358 * timers and tcp_discardcb(). 359 * 360 * KASSERT(inp != NULL, ("tcp_timer_persist: inp == NULL")); 361 */ 362 if (inp == NULL) { 363 tcp_timer_race++; 364 INP_INFO_WUNLOCK(&tcbinfo); 365 return; 366 } 367 INP_LOCK(inp); 368 if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_persist) 369 || !callout_active(&tp->t_timers->tt_persist)) { 370 INP_UNLOCK(inp); 371 INP_INFO_WUNLOCK(&tcbinfo); 372 return; 373 } 374 callout_deactivate(&tp->t_timers->tt_persist); 375 /* 376 * Persistance timer into zero window. 377 * Force a byte to be output, if possible. 378 */ 379 tcpstat.tcps_persisttimeo++; 380 /* 381 * Hack: if the peer is dead/unreachable, we do not 382 * time out if the window is closed. After a full 383 * backoff, drop the connection if the idle time 384 * (no responses to probes) reaches the maximum 385 * backoff that we would use if retransmitting. 386 */ 387 if (tp->t_rxtshift == TCP_MAXRXTSHIFT && 388 ((ticks - tp->t_rcvtime) >= tcp_maxpersistidle || 389 (ticks - tp->t_rcvtime) >= TCP_REXMTVAL(tp) * tcp_totbackoff)) { 390 tcpstat.tcps_persistdrop++; 391 tp = tcp_drop(tp, ETIMEDOUT); 392 goto out; 393 } 394 tcp_setpersist(tp); 395 tp->t_flags |= TF_FORCEDATA; 396 (void) tcp_output(tp); 397 tp->t_flags &= ~TF_FORCEDATA; 398 399 out: 400 #ifdef TCPDEBUG 401 if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG) 402 tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO); 403 #endif 404 if (tp != NULL) 405 INP_UNLOCK(inp); 406 INP_INFO_WUNLOCK(&tcbinfo); 407 } 408 409 void 410 tcp_timer_rexmt(void * xtp) 411 { 412 struct tcpcb *tp = xtp; 413 int rexmt; 414 int headlocked; 415 struct inpcb *inp; 416 #ifdef TCPDEBUG 417 int ostate; 418 419 ostate = tp->t_state; 420 #endif 421 INP_INFO_WLOCK(&tcbinfo); 422 headlocked = 1; 423 inp = tp->t_inpcb; 424 /* 425 * XXXRW: While this assert is in fact correct, bugs in the tcpcb 426 * tear-down mean we need it as a work-around for races between 427 * timers and tcp_discardcb(). 428 * 429 * KASSERT(inp != NULL, ("tcp_timer_rexmt: inp == NULL")); 430 */ 431 if (inp == NULL) { 432 tcp_timer_race++; 433 INP_INFO_WUNLOCK(&tcbinfo); 434 return; 435 } 436 INP_LOCK(inp); 437 if ((inp->inp_vflag & INP_DROPPED) || callout_pending(&tp->t_timers->tt_rexmt) 438 || !callout_active(&tp->t_timers->tt_rexmt)) { 439 INP_UNLOCK(inp); 440 INP_INFO_WUNLOCK(&tcbinfo); 441 return; 442 } 443 callout_deactivate(&tp->t_timers->tt_rexmt); 444 tcp_free_sackholes(tp); 445 /* 446 * Retransmission timer went off. Message has not 447 * been acked within retransmit interval. Back off 448 * to a longer retransmit interval and retransmit one segment. 449 */ 450 if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { 451 tp->t_rxtshift = TCP_MAXRXTSHIFT; 452 tcpstat.tcps_timeoutdrop++; 453 tp = tcp_drop(tp, tp->t_softerror ? 454 tp->t_softerror : ETIMEDOUT); 455 goto out; 456 } 457 INP_INFO_WUNLOCK(&tcbinfo); 458 headlocked = 0; 459 if (tp->t_rxtshift == 1) { 460 /* 461 * first retransmit; record ssthresh and cwnd so they can 462 * be recovered if this turns out to be a "bad" retransmit. 463 * A retransmit is considered "bad" if an ACK for this 464 * segment is received within RTT/2 interval; the assumption 465 * here is that the ACK was already in flight. See 466 * "On Estimating End-to-End Network Path Properties" by 467 * Allman and Paxson for more details. 468 */ 469 tp->snd_cwnd_prev = tp->snd_cwnd; 470 tp->snd_ssthresh_prev = tp->snd_ssthresh; 471 tp->snd_recover_prev = tp->snd_recover; 472 if (IN_FASTRECOVERY(tp)) 473 tp->t_flags |= TF_WASFRECOVERY; 474 else 475 tp->t_flags &= ~TF_WASFRECOVERY; 476 tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); 477 } 478 tcpstat.tcps_rexmttimeo++; 479 if (tp->t_state == TCPS_SYN_SENT) 480 rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift]; 481 else 482 rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; 483 TCPT_RANGESET(tp->t_rxtcur, rexmt, 484 tp->t_rttmin, TCPTV_REXMTMAX); 485 /* 486 * Disable rfc1323 if we havn't got any response to 487 * our third SYN to work-around some broken terminal servers 488 * (most of which have hopefully been retired) that have bad VJ 489 * header compression code which trashes TCP segments containing 490 * unknown-to-them TCP options. 491 */ 492 if ((tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3)) 493 tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP); 494 /* 495 * If we backed off this far, our srtt estimate is probably bogus. 496 * Clobber it so we'll take the next rtt measurement as our srtt; 497 * move the current srtt into rttvar to keep the current 498 * retransmit times until then. 499 */ 500 if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { 501 #ifdef INET6 502 if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) 503 in6_losing(tp->t_inpcb); 504 else 505 #endif 506 tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); 507 tp->t_srtt = 0; 508 } 509 tp->snd_nxt = tp->snd_una; 510 tp->snd_recover = tp->snd_max; 511 /* 512 * Force a segment to be sent. 513 */ 514 tp->t_flags |= TF_ACKNOW; 515 /* 516 * If timing a segment in this window, stop the timer. 517 */ 518 tp->t_rtttime = 0; 519 /* 520 * Close the congestion window down to one segment 521 * (we'll open it by one segment for each ack we get). 522 * Since we probably have a window's worth of unacked 523 * data accumulated, this "slow start" keeps us from 524 * dumping all that data as back-to-back packets (which 525 * might overwhelm an intermediate gateway). 526 * 527 * There are two phases to the opening: Initially we 528 * open by one mss on each ack. This makes the window 529 * size increase exponentially with time. If the 530 * window is larger than the path can handle, this 531 * exponential growth results in dropped packet(s) 532 * almost immediately. To get more time between 533 * drops but still "push" the network to take advantage 534 * of improving conditions, we switch from exponential 535 * to linear window opening at some threshhold size. 536 * For a threshhold, we use half the current window 537 * size, truncated to a multiple of the mss. 538 * 539 * (the minimum cwnd that will give us exponential 540 * growth is 2 mss. We don't allow the threshhold 541 * to go below this.) 542 */ 543 { 544 u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg; 545 if (win < 2) 546 win = 2; 547 tp->snd_cwnd = tp->t_maxseg; 548 tp->snd_ssthresh = win * tp->t_maxseg; 549 tp->t_dupacks = 0; 550 } 551 EXIT_FASTRECOVERY(tp); 552 (void) tcp_output(tp); 553 554 out: 555 #ifdef TCPDEBUG 556 if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) 557 tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, 558 PRU_SLOWTIMO); 559 #endif 560 if (tp != NULL) 561 INP_UNLOCK(inp); 562 if (headlocked) 563 INP_INFO_WUNLOCK(&tcbinfo); 564 } 565 566 void 567 tcp_timer_activate(struct tcpcb *tp, int timer_type, u_int delta) 568 { 569 struct callout *t_callout; 570 void *f_callout; 571 572 switch (timer_type) { 573 case TT_DELACK: 574 t_callout = &tp->t_timers->tt_delack; 575 f_callout = tcp_timer_delack; 576 break; 577 case TT_REXMT: 578 t_callout = &tp->t_timers->tt_rexmt; 579 f_callout = tcp_timer_rexmt; 580 break; 581 case TT_PERSIST: 582 t_callout = &tp->t_timers->tt_persist; 583 f_callout = tcp_timer_persist; 584 break; 585 case TT_KEEP: 586 t_callout = &tp->t_timers->tt_keep; 587 f_callout = tcp_timer_keep; 588 break; 589 case TT_2MSL: 590 t_callout = &tp->t_timers->tt_2msl; 591 f_callout = tcp_timer_2msl; 592 break; 593 default: 594 panic("bad timer_type"); 595 } 596 if (delta == 0) { 597 callout_stop(t_callout); 598 } else { 599 callout_reset(t_callout, delta, f_callout, tp); 600 } 601 } 602 603 int 604 tcp_timer_active(struct tcpcb *tp, int timer_type) 605 { 606 struct callout *t_callout; 607 608 switch (timer_type) { 609 case TT_DELACK: 610 t_callout = &tp->t_timers->tt_delack; 611 break; 612 case TT_REXMT: 613 t_callout = &tp->t_timers->tt_rexmt; 614 break; 615 case TT_PERSIST: 616 t_callout = &tp->t_timers->tt_persist; 617 break; 618 case TT_KEEP: 619 t_callout = &tp->t_timers->tt_keep; 620 break; 621 case TT_2MSL: 622 t_callout = &tp->t_timers->tt_2msl; 623 break; 624 default: 625 panic("bad timer_type"); 626 } 627 return callout_active(t_callout); 628 } 629